Here is the full list of all 27 Gear Up achievements.
Destroy 1500 enemies
Win 20 deathmatch rounds.
Destroy at least seven different opponents in a team game mode.
Repair 30000 armor in lifetime.
Repair (1250) armor in one round of a team game mode.
Destroy 20 enemies with the Grayhound (saws).
Destroy 10 enemies with the default starter cannon.
Drown in the water at least once.
Win 20 team deathmatch rounds.
Win a TDM round overwhelmingly, with a ratio of 4:1 or higher.
Killed a deserting enemy
Assist in capturing at least 20 conquest towers in a single round.
10 kills in a row
6 kills in a row
Recieve 500 damage without being destroyed in a round.
Win 20 conquest rounds.
Destroy 100 enemies
Destroy 75 enemies
Destroy 50 enemies
Capture a conquest tower together with 3 or more teammates.
Win a Conquest round overwhelmingly, with a ratio of 4:1 or higher.
Win 3 conquest rounds.
Destroy 25 enemies
4 kills in a row
Back playing after more than one week of Gear Up absence.
3 kills in a row
2 kills in a row